Children
have greater risk of exposure and greater risk of harm compared
to adults for many reasons that are unique to each developmental
stage.

Environmental
health researchers increasingly recognize that a variety of health
problems may be attributed in part to exposure to environmental
factors.

What
kinds of effects, clinical or otherwise, can be due to exposure
to environmental factors?

Environmentally
influenced health problems are a challenge to diagnose since most
present with non-specific symptoms that are commonly missed
and very few have been adequately characterized.

What can the
clinician do?

What can
parents do?

Introduction

The Children’s Environmental Health Project was designed by the
Canadian Association of Physicians for the Environment (CAPE). It
is intended to introduce clinicians (and their patients) to the
fundamentals and broad context of children’s environmental health
issues. Information on the health effects from environmental exposures
is presented in a systems approach.

Five
units summarize the current scientific research regarding environmental
influences on: 1) respiratory health, 2) neurobehavioural development,
3) cancer and immune functioning, 4) dermatological health, and
5) reproductive health and congenital anomalies in the young. The
project also covers environmental history-taking and provides links
to additional resources that may be useful to the interested individual.
Lastly, we provide a commentary on the physician’s role in primary
prevention of environmental health problems in children.

What is environmental health?

The field of environmental health focusses on the relationships
between human health and well being and the influence of the physical,
social and societal environments. The physical environment encompasses
both natural and built aspects. The latter has the greatest influence
on human health since we are largely an urban society and spend
the vast majority of our time indoors, in homes, buildings or
cars. In industrialized countries, environmental health research
has come increasingly to focus on the impact of the physical,
chemical and biological contaminants that abound in the environment
as a result of our consumer and industrial society.

Our understanding of the environmenthealth interface has
progressed because of two relatively recent insights: First, we
recognize that the unprecedented environmental changes of the
last half-century (i.e., global warming, reduction in atmospheric
ozone, loss of biodiversity, pervasiveness of toxic environmental
contaminants, etc.) are affecting global population health. The
second and arguably equally significant insight has been that
children have greater vulnerability to environmental hazards and
are inadequately protected by current regulatory standards. Efforts
to redress this situation have shaped the current thrust in environmental
health research toward preventing further harm to children’s health.

How are children unique?

Children are not "little adults." We know that children
have greater risk of exposure and greater risk of harm compared
to adults for many reasons that are unique to each developmental
stage.

Their behaviour and activity patterns bring them into greater
contact with toxins.

Children have important biological differences. Immature developing
organs and tissues are more vulnerable to harm from toxic exposures.
Immature metabolic and physiological systems less effectively
protect the child from toxic exposure and effects.

Children have additional pathways of exposure that are not applicable
to adults, e.g., in utero, via breast milk and via products such
as toys, clothing, etc.

In the words of the former US EPA scientist Dr. Lynn Goldman,
children also have a longer "shelf life." They have
much more of their life ahead of them during which time they will
be exposed and may develop health problems as a result.

Finally, children are more often involuntarily exposed and unable
to avoid exposures of their own accord.

What kinds of environmental factors can have an effect on children’s
health?

There is a daunting array of environmental agents to which people
are exposed through various means. Many of these agents can be
considered harmful to humans, especially children.

Chemical and metal pollutants alone account for several
tens of thousands of substances that are in use annually. Pesticides
are an important category of such contaminants that are commonly
present in the environment.

Physical agents that have been studied for their effects
on children’s health include electromagnetic frequency, radiation,
ultraviolet radiation, radon and radionuclides.

Examples of biological agents that influence children’s
health include molds, fungi, bacteria and allergens such as pet
dander and dust mites.

Environmental tobacco smoke (ETS) is a mixture of several
toxic compounds and is the primary cause of poor indoor air quality
and respiratory health problems in children.

Many potential factors exist inthe built environment,
includingunsafe housing, poor indoor air quality (contributed
by many of the factors above such as dampness and mould) and unhealthy
communities (where there is substantial traffic, lack of safe
play areas, unsafe streets, noise, etc.)

Finally, poor children generally experience the worst
in environmental influences on health. Poor communities are most
often downwind, downstream and downhill from major sources of
environmental contamination. Their communities and homes frequently
are in the worst condition and their parents often work at jobs
that expose them to contaminants or other hazards that may be
brought home from the workplace.

What kinds of effects, clinical or otherwise, can be due to exposure
to environmental factors?

Environmental health researchers increasingly recognize that
a variety of health problems may be attributed in part to exposure
to environmental factors. The focus here is on chronic, low-level
exposures, where the evidence for causation remains somewhat
elusive and yet there is potential for many children to be affected.

Some studies have noted increases in spontaneous abortion, stillbirth
rates and congenital birth defects in the babies of women exposed
during pregnancy to various contaminants such as solvents, pesticides,
PCBs, metals, chlorine disinfection by-products in drinking water
and ionizing radiation.

Impairment of behavioural, cognitive and neurological development
may result from exposure early in life to neurotoxins such as
lead and methylmercury. Lowered IQ, reduced attention span, learning
disabilities and behavioural problems such as aggression are subclinical
symptoms associated with exposure to low levels of lead.

There have been substantial increases in childhood asthma, allergies
and respiratory problems in recent decades. There is good evidence
that air pollutants trigger attacks in asthmatic children causing
them to miss school and attend at hospital or their doctor.

An increase in certain childhood cancers such as leukemia and
bone and brain tumours has also been documented and may be related
to exposure to a variety of chemical and physical agents.

Immune system functioning may be compromised by exposure to
contaminants, either by heightening the immune response or by
suppressing it, thereby leaving the body more vulnerable to infections
and cancer.

Finally, there is considerable concern that some environmental
chemicals may act as endocrine disruptors, altering reproductive
development and thyroid or immune system functioning. Studies
of wildlife and laboratory animals have convincingly documented
hormone disruption from certain contaminants. The effects in humans
are not fully confirmed, although trends observed in industrialized
countries (e.g., declining sperm counts, increasing prevalence
of prostate, testicular and breast cancers, reproductive organ
abnormalities and fertility problems) may be linked with the presence
of endocrine disruptors in the environment.

How does this relate to clinical practice?

Environmentally influenced health problems are a challenge to
diagnose since most present with non-specific symptoms
that are commonly missed and very few have been adequately characterized.
This web resource provides basic background information
to enhance the physician’s understanding of the scope of the problem.
References and links to appropriate sources for in-depth diagnostic
and treatment information are provided as far as possible.

Health professionals can also provide parents and patients with
greater understanding and the awareness to prevent hazardous
exposures to their children. One strategy for such patient
education is to incorporate key questions into the history-taking
routine.

The primary tenet of the Hippocratic Oath is to do
no harm. The medical profession therefore fundamentally endorses
a precautionary approach that strives to protect the child
when there is profound uncertainty and incomplete understanding
of the risks from environmental toxins.

As such, physicians are also lending a powerful leading voice
to the health advocacy organizations influencing environmental
policy – the ultimate means of ensuring protection of children’s
health. Of note, in December, 1999, Dr. Kelly Martin gave testimony
on behalf of CAPE to the federal standing committee on environment
and sustainable development, conveying why Canadian physicians
are concerned about the policies regulating pesticide use.

Precaution and prevention require action at a broader level.
CAPE also urges all physicians to ensure that their own hospitals
and practices are not adding to the burden of environmental damage
that may affect the health of children and future generations.
CAPE has been particularly active in urging that the health care
system become more environmentally sustainable and less harmful
to ecosystem health via the Greening
Health Care theme.

What can the clinician do to better understand the environmental
determinants of childhood illness?

The volume of scientific literature on children’s environmental
health issues is enormous. This web resource aims to summarize
some of the more salient details from a practical, clinical and
preventive perspective and suggests further references and resources
for the interested physician.

A first step might be to become a member
of the Canadian Association of Physicians for the Environment
(or other NGO focussing on children’s environmental health) and
take advantage of the networking and information-sharing that
extends from that affiliation.

What can parents do to better understand how the environment can
impact on their children’s health and well being?

Knowledge is power. Parents are encouraged to make use of the
information on prevention in this site.

Parents may also find the suggested links to be of value. Several
sites geared specifically for the lay public are highlighted as
relevant links for parents.